Spatial and seasonal variations in C3Hx hydrocarbon abundance in Titan’s stratosphere from Cassini CIRS observations

•We fit the spectrum propene in Titan’s stratosphere for the first time.•Propene is present in Titan’s stratosphere at 3–11 ppbv within 60° of the equator.•Equatorward of 60°, propene is most abundant within 20° of the equator.•Using new line data we propose a 3-σ upper-limit of for allene of 2.5 ppbv.